The value provided for parameter isn't in the correct format - Exchange Public Folder

This blog post describes how to fix the error 'The value provided for parameter isn't in the correct format. The correct format is "\<FolderPath>".'

Cause

This error can occur when creating a new public folder on Microsoft Exchange 2016.  In the screenshot below, I have specified an invalid folder name, however, Exchange still attempts to create the public folder as there is no validation on the text box.

You can see the invalid public folder in the list of public folders:

As expected, Exchange can't handle an invalid folder name, you get an error if you try to navigate into this folder:

Resolution

To fix the issue, delete the invalid folder name and create a new folder without using any invalid characters: